Preheat oven to 400 degrees. Toss the vegetables with olive oil, season with salt and pepper and spread on a parchment-lined sheet pan. Roast for 20 minutes, or until veggies are soft and lightly browned.
Toss the cornbread cubes with the olive oil and thyme, lay on a separate sheet pan and bake for 10-15 minutes, until lightly browned and crisp.
While the croutons and vegetables are baking, combine the dressing ingredients in a jar and shake until well combined.
To prepare the salad, toss the spinach, vegetables, croutons, and cheese with the dressing. Divide between 4 plates and serve.